Title: Characteristics of Interdecadal Variability of Spring Precipitation in North China and Its Possible Cause
Abstract: The characteristics of the interdecadal variability of spring(MAM) precipitation in China,especially in North China,are analyzed by using the observed data at 160 observational stations of China and 80 observational stations in North China during 1951—2000.The analyzed results show that the spring rainfall's variability in North China have an obvious interdecadal variability and the variation can be divided into three stages interdecadal time-scale from 1951 to 2000.The period of 1951—1965 was a period of below normal of spring rainfall in North China.And during the period of 1966—1976,spring rainfall was still below normal,and it obviously decreased and droughts were severe in spring.However,the period of 1977—2000 was a period of above normal of spring rainfall in North China,especially,the rainfall was more obvious in May and June of this period than that in the period of 1966—1976.Moreover,there was an opposite interdecadal variability between spring and summer precipitation.In order to explain the cause of the interdecadal variability of spring rainfall in North China,the interdecadal variability of the East Asian circulation anomaly in spring is analyzed by using the monthly mean wind field at 700 hPa of the ERA 40 reanalysis data of ECMWF during 1958—2000.The analyzed results show that there was an obvious anticyclonic anomaly circulation over the Mongolian Plateau and the northerly wind anomaly distribution over North China before 1965,which caused below normal of rainfall in spring in this region.Moreover, the anomalies of northerly wind were still strong and the northerly wind anomalies were intensified over the eastern part of China and the South China Sea in the period of 1966—1976,which caused the further decrease of the spring rainfall in this region.However,up to the period of 1977—2000,an obvious change occurred in the 700 hPa circulation anomaly over East Asia,the southerly wind anomalies appeared over North China and the southerly wind anomalies were intensified over the eastern coast of China.This could cause that the warm and wet air-flow were easily transported from South China into North China,which can cause the increase of spring rainfall in North China.
Publication Year: 2006
Publication Date: 2006-01-01
Language: en
Type: article
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Cited By Count: 6
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